A catalytic combustion device having the function of supplying fuel to a catalyst arranged in the exhaust passage of the internal combustion engine was proposed (See Patent Literature 1, for example). In this device, fuel is supplied to the catalytic combustion section by a main injector, while the fuel injected from a sub injector is ignited by a spark plug, and the catalytic combustion section is pre-heated by the flame.
In a device disclosed in Patent Literature 2, electricity is made to flow between a central electrode and an outer-peripheral electrode incorporated in the catalyst for purifying exhaust gas so as to pre-heat the catalyst before the engine is started.